1. Field
The invention relates to capture of three dimensional data. More specifically, the invention relates to a high speed high resolution scanner to capture three dimensional data about a target.
2. Background
Various scanners exist to capture geometry of three dimensional objects. One class of such scanners uses a laser to project a light pattern onto a target and then determines the dimensions of the target from the interaction of the pattern with the target. As used herein, “target” refers to all or some portion of a three dimensional object. In theory, it would be faster to scan a target using multiple lasers. However, the introduction of multiple lasers creates ambiguity as it is often difficult or impossible to discern which laser is illuminating a pixel of a image sensing array.
To disambiguate multiple lasers, attempts have been made to encode the light pattern. In one such device, color is used to encode different laser stripes. In such a device, each laser emits a different colored stripe. The interaction of each laser stripe with a surface of the object can then be distinguished base on the color of the stripe. Such scanning methods, however, are heat intensive, expensive, and the number of lasers used is limited by the number of different colored lasers available. In other devices, a dot-dash pattern may be used to encode each laser stripe. Problems arise in such scanning methods, however, because when scanning different objects, light captured at the sensing array tends to fall off. Accordingly, it is difficult to discern whether the effect is due to the dot-dash patterned stripe or the geometry of the object. This can result in erroneous depth determinations.
It has further been a challenge of multiple laser scanners to maintain a small, compact size while still being able to capture images of relatively large targets. Generally, the larger the image to be captured, the larger the scanner must be.